INTRODUCTION: Evidence comparing adult and child preferences consistently report higher utility values for child health states (HS). Explanations for these findings have not been documented yet.

AIM: To investigate reasons why child HS are valued differently.

METHODS: Eighty respondents (UK, Belgium, The Netherlands) participated in 1.5-hour face-to-face interviews. Respondents valued four HS from two perspectives (8-year-old child, 40-year-old adult) using VAS and TTO. Thirty-two respondents also participated in think-aloud interviews. Audio-recordings were analysed in NVIVO by two independent coders. Statements, nodes and themes were reviewed cyclically until consensus was reached.

RESULTS:

Quantitative results: Significantly higher VAS values and TTO utilities were observed for children: +0.026, +0.112, +0.377 and +0.294 higher utilities for mild, moderate, severe and worst HS (all p<0.01).

Qualitative results: 1,221 pages of transcripts resulted in 303 coded statements. Five themes were present in child and adult valuation, though with a different interpretation. Inter-generational responsibility and dependency (Childhood is a crucial time for forming life skills based on new experiences; adulthood is an important time to take care of the family); Staying alive is important (Life is worth living even with impaired HRQoL, for children and adults); Awareness of poor HRQoL and ability to make decisions (Children have difficulties comprehending poor HRQoL and their parents make their health care decision; adults can assess their HRQoL and decide for themselves); Coping ability (Children are flexible and resilient; adults have experience with dealing with difficulties); and Practical organisation of care (Children are unconditionally cared for by their parents; adults are able to organise and pay for care).

Mixed methods: Comparing qualitative statements with respondents’ TTO values confirmed concordance between the results.

CONCLUSION: Respondents showed a lower willingness-to-trade LY for achieving higher HRQoL in children. This finding may impact the youth valuation protocol and the ICER threshold used in paediatric HTA.